Walking speed and global cognition: results from the OKLAHOMA Study

Executive functioning and processing speed have been related to physical functioning in non-demented, elderly samples; however, the relationship between walking speed and global cognition has not been examined. Six hundred and seventy-five community dwelling older adults were enrolled through their primary care physicians. Walking speed was assessed on a 50-foot course at usual pace. Global cognition was assessed with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Total Scale score. After adjusting for age, gender, and education, there was a strong inverse relationship between walking speed and global cognition, with slower walkers performing worse on the cognitive measures, faster walkers performing better on the cognitive measures, and the intermediate walkers performing in the middle. In these older adults, global cognition was related to walking speed.     

Walking Speed and Global Cognition: Results from the OKLAHOMA Study

ABSTRACT

Executive functioning and processing speed have been related to physical functioning in non-demented, elderly samples; however, the relationship between walking speed and global cognition has not been examined. Six hundred and seventy-five community dwelling older adults were enrolled through their primary care physicians. Walking speed was assessed on a 50-foot course at usual pace. Global cognition was assessed with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Total Scale score. After adjusting for age, gender, and education, there was a strong inverse relationship between walking speed and global cognition, with slower walkers performing worse on the cognitive measures, faster walkers performing better on the cognitive measures, and the intermediate walkers performing in the middle. In these older adults, global cognition was related to walking speed.     

Walking perception by walking observers

People frequently analyze the actions of other people for the purpose of action coordination. To understand whether such self-relative action perception differs from other-relative action perception, the authors had observers either compare their own walking speed with that of a point-light walker or compare the walking speeds of 2 point-light walkers. In Experiment 1, observers walked, bicycled, or stood while performing a gait-speed discrimination task. Walking observers demonstrated the poorest sensitivity to walking speed, suggesting that perception and performance of the same action alters visual-motion processes. Experiments 2-6 demonstrated that the processes used during self-relative and other-relative action perception differ significantly in their dependence on observers' previous motor experience, current motor effort, and potential for action coordination. These results suggest that the visual analysis of human motion during traditional laboratory studies can differ substantially from the visual analysis of human movement under more realistic conditions.     

Discovery of the Pendulum and Spring Dynamics in the Early Stages of Walking

The authors investigated the self-selected, overground walking patterns of 7 children (aged 11 months to 1 year, 5 months) at the initiation of walking (brand-new walkers [BNWs]) and for the next 6 months at 1-month intervals. Walking speed, stride length, and stride frequency increased significantly between the first 2 visits without significant changes in height and weight. The authors calculated sagittal plane angular accelerations of the center of mass over the foot for each step as an indicator of the escapement pulse. Results for the acceleration profiles changed after the 1st visit to positive, single-peaked accelerations that occurred < 0.20 s after initial foot contact. Increases in sagittal plane hip angular displacement and decreases in frontal plane pelvic angular displacement were observed. The pattern changes suggest that children quickly discover appropriately timed and directed escapements that initiate and support the conservative sagittal plane pendulum and spring dynamics observed in older children.     

Psychosocial Correlates and Outcomes of Yoga or Walking Among Older Adults

Few researchers have compared psychological correlates and outcomes of yoga with more traditional forms of exercise. The authors' primary aim was to compare changes in the psychosocial outcomes of mood and state anxiety produced by an acute bout of yoga or walking among older adults. The secondary aim was to compare selected psychosocial correlates of activity. Participants were 51 adults who were 50 years of age or older who walked for exercise or participated in a yoga class. Results revealed that yoga participants had significantly greater levels of depression and perceived barriers to exercise, and lower quality of life than did walkers. With control for these differences, yoga practitioners had improved levels of fatigue pre- to postsession, compared with walkers. With control for differences in demographic variables, these changes were no longer significant. It is possible that yoga practitioners seek out mindful-based exercise to cope with greater levels of depression and lower levels of quality of life.     

The development of compensatory stepping skills in children

The development of the ability to use the step for balance recovery was studied among twenty-five 9- to 19-month-old children. The children were grouped according to walking experience (4 levels) and exposed to backward support surface translations, 8 cm in amplitude, under 3 velocity conditions: 15, 20, and 25 cm/s. New walkers (up to 2 weeks' walking experience) used the step infrequently and ineffectively in response to threats to balance. Intermediate walkers (1-3 months' walking experience) showed an increasing use of the step and significant improvement in step execution compared with new walkers. Advanced walkers (>3; months' walking experience) experienced no falls throughout the protocol, capturing balance with feet-in-place or step responses under all perturbation conditions. A significant developmental transition in the emergence of the compensatory step occurred between the new walker and the intermediate walker experience levels, that is, within the first 3 months of walking experience. Three to 6 months' experience was required for the development of an effective stepping response. A concomitant change in mediolateral stability paralleled the emergence of compensatory stepping.     

The Development of Compensatory Stepping Skills in Children

The development of the ability to use the step for balance recovery was studied among twenty-five 9- to 19-month-old children. The children were grouped according to walking experience (4 levels) and exposed to backward support surface translations, 8 cm in amplitude, under 3 velocity conditions: 15, 20, and 25 cm/s. New walkers (up to 2 weeks' walking experience) used the step infrequently and ineffectively in response to threats to balance. Intermediate walkers (1-3 months' walking experience) showed an increasing use of the step and significant improvement in step execution compared with new walkers. Advanced walkers (> 3 months' walking experience) experienced no falls throughout the protocol, capturing balance with feet-in-place or step responses under all perturbation conditions. A significant developmental transition in the emergence of the compensatory step occurred between the new walker and the intermediate walker experience levels, that is, within the first 3 months of walking experience. Three to 6 months' experience was required for the development of an effective stepping response. A concomitant change in mediolateral stability paralleled the emergence of compensatory stepping.     

The Influence of Walking Speed and Prior Practice on Locomotor Distance Estimation

In an attempt to reconcile discrepant findings in the literature (Elliott, 1986; Thomson, 1983), walking speed, prior practice, and walking delay were manipulated to determine if they had an impact on locomotor distance estimation. Contrary to suggestions by Thomson (1986), walking variability in the direction of locomotion depended only on a subject’s initial distance from the targets.     

Interlimb coordination in prosthetic walking: effects of asymmetry and walking velocity

The present study focuses on interlimb coordination in walking with an above-knee prosthesis using concepts and tools of dynamical systems theory (DST). Prosthetic walkers are an interesting group to investigate from this theory because their locomotory system is inherently asymmetric, while, according to DST, coordinative stability may be expected to be reduced as a function of the asymmetry of the oscillating components. Furthermore, previous work on locomotion motivated from DST has shown that the stability of interlimb coordination increases with walking velocity, leading to the additional expectation that the anticipated destabilizing effect of the prosthesis-induced asymmetry may be diminished at higher walking velocities. To examine these expectations, an experiment was conducted aimed at comparing interlimb coordination during treadmill walking between seven participants with an above-knee prosthesis and seven controls across a range of walking velocities. The observed gait patterns were analyzed in terms of standard gait measures (i.e., absolute and relative swing, stance and step times) and interlimb coordination measures (i.e., relative phase and frequency locking). As expected, the asymmetry brought about by the prosthesis led to a decrease in the stability of the coordination between the legs as compared to the control group, while coordinative stability increased with increasing walking velocity in both groups in the absence of a significant interaction. In addition, the 2:1 frequency coordination between arm and leg movements that is generally observed in healthy walkers at low walking velocities was absent in the prosthetic walkers. Collectively, these results suggest that both stability and adaptability of coordination are reduced in prosthetic walkers but may be enhanced by training them to walk at higher velocities.     

Why walkers slip: shine is not a reliable cue for slippery ground

In a series of four studies, we investigated the visual cues that walkers use to predict slippery ground surfaces and tested whether visual information is reliable for specifying low-friction conditions. In Study 1, 91% of participants surveyed responded that they would use shine to identify upcoming slippery ground. Studies 2-4 confirmed participants' reliance on shine to predict slip. Participants viewed ground surfaces varying in gloss, paint color, and viewing distance under indoor and outdoor lighting conditions. Shine and slip ratings and functional walking judgments were related to surface gloss level and to surface coefficient of friction (COF). However, judgments were strongly affected by surface color, viewing distance, and lighting conditions--extraneous factors that do not change the surface COF. Results suggest that, although walkers rely on shine to predict slippery ground, shine is not a reliable visual cue for friction. Poor visual information for friction may underlie the high prevalence of friction-related slips and falls.     

The role of crawling and walking experience in infant spatial memory

This research explored infants' use of place learning and cue learning in a locomotor task across the transition from crawling to walking. Novice and expert crawling and walking infants were observed in a novel locomotor task-finding a hidden goal location in a large space. In Experiment 1, infants were tested with distal landmarks. Infants with fewer than 6 weeks of experience, either crawling or walking, could not find the goal location. All infants with more locomotor experience were more successful. Learning did not transfer across the transition to walking. In Experiment 2, novice and expert crawlers and walkers were tested with a direct landmark. Again, novice crawlers and walkers with fewer than 6 weeks of experience could not find the goal, whereas those with more experience could. Taken together, these findings suggest that infants' spatial learning is inextricably linked to mode of locomotion.     

Person identification from biological motion: effects of structural and kinematic cues

Human observers are able to identify a person based on his or her gait. However, little is known about the underlying mechanisms and the kind of information used to accomplish such a task. In this study, participants learned to discriminate seven male walkers shown as point-light displays from frontal, half-profile, or profile view. The displays were gradually normalized with respect to size, shape, and walking frequency, and identification performance was measured. All observers quickly learned to discriminate the walkers, but there was an overall advantage in favor of the frontal view. No effect of size normalization was found, but performance deteriorated when shape or walking frequency was normalized. Presenting the walkers from novel viewpoints resulted in a further decrease in performance. However, even after applying all normalization steps and rotating the walker by 90 degrees, recognition performance was still nearly three times higher than chance level.     

Reaction Time of Healthy Older Adults Is Reduced While Walking Fast

Attentional requirements of walking at various speeds in older adults were examined. Twenty healthy older adults (69.9?±?2.77?years; 8 males) were asked to walk a distance of 10?m at a self-selected speed as well as 30% quicker and 30% slower. Concurrently, reaction time (RT) was evaluated by having participants respond as fast as possible to randomly presented auditory stimuli. Results reveal that an accelerated walking speed generated faster RT than slow and self-selected speeds, while no difference was found between the latter. Faster RTs during an accelerated walking speed may have been precipitated by the reduced equilibrium demands of the task.     

The step cycle organization of infant walkers

To walk independently, the human infant must coordinate its multisegmented body to achieve both postural stability and forward mobility. In this experiment, we sought evidence of the form this coordination takes in infants who have been walking 3 to 10 months. Using the Philippson phases to represent the step cycle, we analyzed film records of infants and adults walking at speeds from 2 to 4 km/hr. Our results reveal a clear relationship between walking speed and the F and E(3) Philippson phases of the step cycle in both the young walkers and the adults. Indeed, across all four phases of the step cycle, the infants exhibited an organization that was almost identical to that of the mature walkers.     

Walking on music

The present study focuses on the intricate relationship between human body movement and music, in particular on how music may influence the way humans walk. In an experiment, participants were asked to synchronize their walking tempo with the tempo of musical and metronome stimuli. The walking tempo and walking speed were measured. The tempi of the stimuli varied between 50 and 190 beats per minute. The data revealed that people walk faster on music than on metronome stimuli and that walking on music can be modeled as a resonance phenomenon that is related to the perceptual resonance phenomenon as described by Van Noorden and Moelants (Van Noorden, L., & Moelants, D. (1999). Resonance in the perception of musical pulse. Journal of New Music Research, 28, 43-66).     

Prospective Examination of Self‐Regulatory Efficacy in Predicting Walking for Active Transportation: A Social Cognitive Theory Approach

Walking for transportation is associated with health benefits. Minimal theory‐based research has examined social cognitive and environmental predictors. This study examined social cognitions (self‐regulatory efficacy to plan/schedule and overcome barriers; distance and travel time cognitions) and an environmental factor (proximity) as predictors of walking for transportation. Participants (n = 105) were university students, faculty, and staff, living within a walkable distance to campus. Social cognitions and proximity measures were completed at baseline, followed by walking for transportation to/from the campus over 2 weeks. A hierarchical multiple regression analysis predicted walking (R²_adjusted = .55; p < .05). Self‐regulatory efficacy to plan/schedule and overcome barriers were independent predictors (p's < .01). Findings supported theoretical contentions that self‐regulatory efficacy predicts walking for transportation.     

Kinematic cues for person identification from biological motion

We examined the role of kinematic information for person identification. Observers learned to name seven walkers shown as point-light displays that were normalized by their size, shape, and gait frequency under a frontal, half-profile, or profile view. In two experiments, we analyzed the impact of individual harmonics as created by a Fourier analysis of a walking pattern, as well as the relative importance of the amplitude and the phase spectra in walkers shown from different viewpoints. The first harmonic contained most of the individual information, but performance was also above chance level when only the second harmonic was available. Normalization of the amplitude of a walking pattern resulted in a severe deterioration of performance, whereas the relative phase of the point lights was only used from a frontal viewpoint. No overall advantage for a single learning viewpoint was found, and there is considerable generalization to novel testing viewpoints.     

Walking with avatars: Gait-related visual information for following a virtual leader

Dynamic situations, such as interactive sports or walking on a busy street, impose high demands on a person’s ability to interact with (others in) its environment (i.e., ‘interact-ability’). The current study examined how distance regulation, a fundamental component of these interactions, is mediated by different sources of visual information. Participants were presented with a back and forwards moving virtual leader, which they had to follow by walking back and forwards themselves. We presented the leader in several appearances that differed in the presence of segmental (i.e., relative movements of body segments), cadence-related (i.e., sway and bounce), and global (i.e., optical expansion-compression) information. Results indicated that removing segmental motion information from the virtual leader significantly deteriorated both temporal synchronization and spatial accuracy of the follower to the leader, especially when the movement path of the leader was less regular/predictable. However, no difference was found between cadence-related and global motion information appearances. We argue that regulating distance with others effectively requires a versatile attunement to segmental and global motion information depending on the specific task demands. The results further support the notion that detection of especially segmental information allows for more timely ‘anticipatory’ tuning to another person’s locomotor movements and intentions.     

Walking dreams in congenital and acquired paraplegia

To test if dreams contain remote or never-experienced motor skills, we collected during 6 weeks dream reports from 15 paraplegics and 15 healthy subjects. In 9/10 subjects with spinal cord injury and in 5/5 with congenital paraplegia, voluntary leg movements were reported during dream, including feelings of walking (46%), running (8.6%), dancing (8%), standing up (6.3%), bicycling (6.3%), and practicing sports (skiing, playing basketball, swimming). Paraplegia patients experienced walking dreams (38.2%) just as often as controls (28.7%). There was no correlation between the frequency of walking dreams and the duration of paraplegia. In contrast, patients were rarely paraplegic in dreams. Subjects who had never walked or stopped walking 4–64 years prior to this study still experience walking in their dreams, suggesting that a cerebral walking program, either genetic or more probably developed via mirror neurons (activated when observing others performing an action) is reactivated during sleep.